Research On Navigation Technology Of Mobile Robot Based On Two-dimensional Code Landmark

With the development of economy and the importance that countries attach to the field of robots,the technology of mobile robots at home and abroad has been developed rapidly,and more and more industries are involved in mobile robots.The application of robots in industrial production can liberate labor force and improve production efficiency.Mobile robots have many navigation methods,such as vision navigation,inertial navigation,electromagnetic navigation,etc.At present,in the storage and logistics industry,two-dimensional code landmark is mainly used to realize the autonomous navigation of robots.However,in order to fully apply robots to warehousing logistics,it is necessary to solve many technical problems,such as robot positioning,path planning,motion control,scheduling and so on.Choosing an appropriate navigation method in a specific industry can save cost,facilitate control and improve the efficiency of multi-robot cooperation.Twodimensional code navigation has the advantages of small size,low cost,and accurate positioning.Therefore,the application of two-dimensional code landmarks to mobile robot navigation technology has very important theoretical and practical significance.First of all,this thesis analyzes the navigation technology,positioning technology,path planning technology of mobile robots and two-dimensional code technology in detail.By comparing the advantages and disadvantages of various navigation methods and two-dimensional codes,based on Data Matrix code,the design of mobile robots navigation system based on two-dimensional code landmark is realized.The system is composed of upper computer monitoring system based on C++ and robot based on ARM processor.Secondly,the global path planning of mobile robots based on twodimensional code landmark is studied.Aiming at the problem of stagnation and slow convergence of ant colony algorithm in the structured grid working environment of two-dimensional code construction,an improved ant colony algorithm is proposed for path planning of two-dimensional code mobile robots.First of all,by limiting the search direction of ants,robots are placed in a structured grid working environment,so that they can only move in the horizontal and vertical directions,thus improving the search efficiency of the algorithm.Then,by introducing the adaptive expectation function and heuristic factor,the state transition probability can be adjusted dynamically to avoid the stagnation of the algorithm and improve the convergence speed of the algorithm.Secondly,to solve the problem that robots takes a long time in the turning process,the extended path length is obtained by introducing the turning influence factor,and then the optimal path is selected according to the extended path length.The experimental results show that the improved ant colony algorithm can plan the optimal path for the twodimensional code mobile robots.Thirdly,the error correction in the operation of robots are studied.Only a few nodes can get the pose information when robots are running in the grid map constructed by two-dimensional code,and robots themselves have system error,which leads to the problem that robots are easy to be out of code when it is running for a long time.In this thesis,the data obtained by two-dimensional code camera,photoelectric encoder and gyroscope are integrated to make up for the shortcomings of less information of the two-dimensional code,and at the same time,the cumulative error of the photoelectric encoder and the gyroscope can also be reduced.According to the motion characteristics of two-wheel drive mobile robots between the two-dimensiona code,the sensor information is used to fine-tune robots to ensure that robots can accurately reach the next two-dimensiona code,and finally realize robots from the starting point to the target point.Finally,the software and hardware platform of the whole system is built and tested in practice.The experiment proves the accuracy of the improved ant colony algorithm and error correction method,and further proves the feasibility of the navigation system designed in thesis.